The SIM (Subscriber Identity Module) Access Profile, SAP, is a protocol over Bluetooth® that allows a terminal, acting as a client, to access a SIM card in another device, acting as a server. (Bluetooth is a registered trademark of Bluetooth SIG, a Delaware corporation with headquarters in Lake Washington Boulevard, Suite 350, Kirkland, Wash.) As an example, a terminal may be a vehicle hands-free kit, sometimes simply referred to as a car kit, and a server may be a driver's cellphone so that the driver may make hand-free calls. Further examples include a cellphone or tablet acting as a client that accesses a remote SIM card in a dongle or other portable device. The portable device may be a wearable device, such as a wristwatch.
At various times, such as for example during an initial network registration procedure, the client needs to access various data stored in the SIM card. To obtain the desired data, the client streams messages containing APDUs (Application Protocol Data Unit) to the server (e.g., driver's cellphone) to request the desired data, and the server responds with messages containing APDUs with the requested data. It is desirable to speed this process up so as to reduce delays, and to reduce power consumption in portable Bluetooth capable devices.